She'd never been in a studio before she started work on Countdown. A sideways step into the less genteel world of 8 Out Of 10 Cats Does Countdown (the Channe4 mash-up which fuses our favourite teatime show with the late-night panel show's more risqué japes), allowed her to show a more cheeky side, one she admits she wouldn't share with her grandparents.'I always say the side of me I show on Countdown is the side I'd show to my gran,' she says.She launches into a very detailed explanation of what these jaunts set out to prove - there's much earnest talk about the latent heat of water, the centre of gravity and angular momentum - but to be honest, you're left wondering how this show ever got past the insurance underwriters; zipwiring through a walof fire at 450°C is pretty hairy, even if she'd been doused with water first. 'The zipwire was to do with the latent heat of water, so if you go through quickly enough the water won't burn off so your skin is protected just by the layer of water.
'Romesh has had a fridge dropped on his head from a massive height and wilbe dangled over some crocodiles this week with just a vacuum cleaner holding him up.
And Ben's had a crossbow fired at his head.'How entertaining.
'Once Strictly was over, there was no professional relationship. Crippled by performance nerves, she underwent a course of cognitive behavioural therapy which she says challenged her thinking, and not just on the dance floor. But now I feel like you can choose your own path.'She's careful not to criticise her ex, or say that getting married, because it was expected of her, was a mistake. It's the marriage that changes everything in other people's perceptions, but for me marriage is a man-made thing. I wanted to buy somewhere because I'm English, my family are here, I will always want somewhere in London.
In Strictly it was very much the professionals and the celebrities. We weren't a couple, he was just my teacher.'She does confess that Strictly was a factor in the break-up of her marriage, but only in that it took her away from home for a while, and gave her thinking space to consider her relationship, which was already in trouble. 'I was always putting myself down, criticising the bad bits, believing the criticism I got and putting the good comments down to someone just being nice. Went to Oxford...'She had a charmed life, but oh so conventional. You go to school, you go to uni, you get a job, you get married, have babies. It shouldn't affect it.' This would suggest she should never have got married at all. 'It felt like the right thing to do.'She insists she and Jamie are still friends, and still very much in contact. We just do what we feel is right, rather than what other people think is normal. But he's nomadic, so I have no idea where he'll want to be.'The old Rachel might have baulked at the apparent lack of security in such a domestic set-up, but she insists that it's 'perfect'.
There are just people who go on TV.'Obviously her stint on Strictly did much to bring her to the masses, and further challenge the idea of her as little more than a sweet girl-next-door who could count.
Running off with her professional partner, though, was perhaps taking this notion a bit far.
'The me on 8 Out Of 10 Cats is the side I'd show to my mates.
This new programme is somewhere in the middle.'Does she feel like a 'real' TV presenter now? For a long time I thought, "I'm not a TV presenter", but now I realise there's no typical route into this business.
'One of them asked me about my work, and I told him, in Russian, that I do numbers on TV. It's Not Rocket Science on ITV sees Rachel, 30, and her co-presenters - comedians and fellow brainboxes Ben Miller, who did a Ph D in solid state physics, and Romesh Ranganathan, an ex-maths teacher - attempt to bring science to the masses. 'People hear the word "science" and they think lab coats and Bunsens. Flying through a walof flames seems tame in comparison to what the men have to do.
He called Pasha over and said, "She says she does numbers on TV. 'Each week one of us risks our lives to prove a scientific theory,' Rachel explains cheerily.
The therapy made me realise I'm a perfectionist, which I never thought I was.'This idea of struggling to live up to an expected standard had been a long-standing issue, she realised. I think girls tend to think like that, especially high achievers. That's what I was doing for a long time.' With no outward signs of it being a problem, clearly. She points out that her marriage, to the sweet boy she'd met at university, was part of that trajectory. Although the marriage produced no children, they did have cats - which posed a custody issue. He gets on well with Pasha, and we're still great friends. I don't feel the pressure any more.'She's just bought a house, and chats away about plans to furnish it, but there's no real sense that this is a family home. 'I've got all the security I need because we're happy.